Hello Peter,

> \start ... \stop mark the boundaries of the local (layout) setup, which
> is defined between \startlocal ... \stoplocal. This way you don't need
> to redefine your old layout after a local (one page) style change.
> ConTeXt returns to the prior layout automatically.
> 
> So deleting them is no good idea (results in extra work for you) :)

Yes, I noticed that... :)

> If you can make a minimal example of your buffer problems...

Ok, I'v attached the example. It seems that If I use 
\start \startlocal and \stop and \stoplocal I get some errors...

Thanks for your help!
Miguel Queirós